The Brahmaputra (/ËŒbrÉ'ËməˈpuËtrÉ™/ [brÉ"mmÉ"put̪rÉ" nÉ"d̪]), also called Tsangpo-Brahmaputrab>, is a trans-boundary river and one of the major rivers of Asia. Majuli is the Riverine island formed by River Brahmaputra in Assam in India.
With its origin in the Angsi Glacier, located on the northern side of the Himalayas in Burang County of Tibet as the Yarlung Tsangpo River, it flows across southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon) and into Arunachal Pradesh (India) where it is known as Dihang or Siang. It flows southwest through the Assam Valley as Brahmaputra and south through Bangladesh as the Jamuna (not to be mistaken with Yamuna of India). In the vast Ganges Delta it merges with the Padma, the main distributary of the Ganges, then the Meghna, before emptying into the Bay of Bengal.
About 1,800 miles (2,900 km) long, the Brahmaputra is an important river for irrigation and transportation. The average depth of the river is 124 feet (38 m) and maximum depth is 380 feet (120 m). The river is prone to catastrophic flooding in spring when the Himalayan snows melt. The average discharge of the river is about 19,300 cubic metres per second (680,000 cu ft/s), and floods can reach over 100,000 cubic metres per second (3,500,000 cu ft/s). It is a classic example of a braided river and is highly susceptible to channel migration and avulsion. It is also one of the few rivers in the world that exhibit a tidal bore. It is navigable for most of its length.
The river drains the Himalaya east of the Indo-Nepal border, southern-central portion of the Tibetan plateau above the Ganges basin, south-eastern portion of Tibet, the Patkai-Bum hills, the northern slopes of the Meghalaya hills, the Assam plains and the northern portion of Bangladesh. The basin, especially south of Tibet is characterized by high levels of rainfall. Kangchenjunga (8,586m) is the only peak above 8,000m and the highest point within the Brahmaputra basin.
The Brahmaputra's upper course was long unknown, and its identity with the Yarlung Tsangpo was only established by exploration in 1884â€"86. This river is often called Tsangpo-Brahmaputra river.
The lower reaches are sacred to Hindus. While most rivers on the Indian subcontinent have female names, this river has a rare male name, as it means "son of Brahma" in Sanskrit (putra means "son").
Course
Tibet
The Brahmaputra river (also called as "Burlung-Buthur" by the Bodo people of Assam), called Yarlung Tsangpo in Tibetan language, originates on the Angsi Glacier located on the northern side of the Himalayas in Burang County of Tibet and not Chema-Yungdung glacier, which was previously identified by geographer Swami Pranavananda in the 1930s. The river is 3,848 kilometres (2,391 mi) long, and its drainage area is 712,035 square kilometres (274,918 sq mi) according to the new findings, while previous documents showed its length varied from 2,900 to 3,350 km and its drainage area between 520,000 and 1.73 million square km. This finding has been given by Mr. Liu Shaochuang, a researcher with the Institute of Remote Sensing Applications under the analysis using expeditions and satellite imagery from the Chinese Academy of Sciences (CAS).
From its source the river runs for nearly 700 miles (1,100 km) in a generally easterly direction between the main range of the Himalayas to the south and the Kailas Range to the north. Throughout its upper course the river is generally known as the Tsangpo (“Purifierâ€); it is also known by its Chinese name (Yarlung Zangbo) and by other local Tibetan names.
In Tibet the Tsangpo receives a number of tributaries. The most important left-bank tributaries are the Raka Zangbo (Raka Tsangpo), which joins the river west of Xigazê (Shigatse), and the Lhasa (Kyi), which flows past the Tibetan capital of Lhasa and joins the Tsangpo at Qüxü. The Nyang Qu (Gyamda) River joins the river from the north at Zela (Tsela Dzong). On the right bank a second river called the Nyang Qu (Nyang Chu) meets the Tsangpo at Xigazê.
After passing Pi (Pe) in Tibet, the river turns suddenly to the north and northeast and cuts a course through a succession of great narrow gorges between the mountainous massifs of Gyala Peri and Namjagbarwa (Namcha Barwa) in a series of rapids and cascades. Thereafter, the river turns south and southwest and flows through a deep gorge (the “Grand Canyon†of the Tsangpo) across the eastern extremity of the Himalayas with canyon walls that extend upward for 16,500 feet (5,000 metres) and more on each side. During that stretch the river enters northern Arunachal Pradesh state in northeastern India, where it is known as the Dihang (or Siang) River, and turns more southerly.
Assam and adjoining region
The Brahmaputra enters India in the state of Arunachal Pradesh, where it is called Siang. It makes a very rapid descent from its original height in Tibet, and finally appears in the plains, where it is called Dihang. It flows for about 35 kilometres (22 mi) and is joined by the Dibang River and the Lohit River at the head of the Assam Valley. Below the Lohit the river is called Brahmaputra, enters the state of Assam and becomes very wideâ€"as wide as 10 kilometres (6 mi) in parts of Assam. It is joined in Sonitpur by the Kameng River (or Jia Bhoreli).
The Dihang, winding out of the mountains, turns toward the southeast and descends into a low-lying basin as it enters northeastern Assam state. Just west of the town of Sadiya, the river again turns to the southwest and is joined by two mountain streams, the Lohit and the Dibang. Below that confluence, about 900 miles (1,450 km) from the Bay of Bengal, the river becomes known conventionally as the Brahmaputra (“Son of Brahmaâ€). In Assam the river is mighty, even in the dry season, and during the rains its banks are more than 5 miles (8 km) apart. As the river follows its braided 450-mile (700-km) course through the valley, it receives several rapidly rushing Himalayan streams, including the Subansiri, Kameng, Bhareli, Dhansiri, Manas, Champamati, Saralbhanga, and Sankosh rivers. The main tributaries from the hills and from the plateau to the south are the Burhi Dihing, the Disang, the Dikhu, and the Kopili.
Between Dibrugarh and Lakhimpur districts the river divides into two channelsâ€"the northern Kherkutia channel and the southern Brahmaputra channel. The two channels join again about 100 kilometres (62 mi) downstream forming the Majuli island, which was, until some time back, the largest river island in the world. At Guwahati, near the ancient pilgrimage centre of Hajo, the Brahmaputra cuts through the rocks of the Shillong Plateau, and is at its narrowest at 1 kilometre (1,100 yd) bank-to-bank. Due to the river's narrow width, the Battle of Saraighat was fought here in March 1671. The first combined rail/road bridge across the Brahmaputra was opened to traffic in April 1962 at Saraighat.
The environment of the Brahmaputra floodplains in Assam have been described as the Brahmaputra Valley semi-evergreen forests ecoregion.
Bangladesh
In Bangladesh, the Brahmaputra is joined by the Teesta River (or Tista), one of its largest tributaries. Below the Teesta, the Brahmaputra splits into two distributary branches. The western branch, which contains the majority of the river's flow, continues due south as the Jamuna (Jomuna) to merge with the lower Ganges, called the Padma River (Pôdda). The eastern branch, formerly the larger but now much smaller, is called the lower or old Brahmaputra (Bromhoputro). It curves southeast to join the Meghna River near Dhaka. The Padma and Meghna converge near Chandpur and flow out into the Bay of Bengal. This final part of the river is called Meghna.
The Brahmaputra enters the plains of Bangladesh after turning south around the Garo Hills below Dhuburi, India. After flowing past Chilmari, Bangladesh, it is joined on its right bank by the Tista River and then follows a 150-mile (240-km) course due south as the Jamuna River. (South of Gaibanda, the Old Brahmaputra leaves the left bank of the main stream and flows past Jamalpur and Mymensingh to join the Meghna River at Bhairab Bazar.) Before its confluence with the Ganges, the Jamuna receives the combined waters of the Baral, Atrai, and Hurasagar rivers on its right bank and becomes the point of departure of the large Dhaleswari River on its left bank. A tributary of the Dhaleswari, the Buriganga (“Old Gangesâ€), flows past Dhaka, the capital of Bangladesh, and joins the Meghna River above Munshiganj.
The Jamuna joins with the Ganges north of Goalundo Ghat, below which, as the Padma, their combined waters flow to the southeast for a distance of about 75 miles (120Â km). After several smaller channels branch off to feed the Ganges-Brahmaputra delta to the south, the main body of the Padma reaches its confluence with the Meghna River near Chandpur and then enters the Bay of Bengal through the Meghna estuary and lesser channels flowing through the delta. The growth of the Ganges-Brahmaputra delta is dominated by tidal processes.
The Ganges Delta, fed by the waters of numerous rivers, including the Ganges and Brahmaputra, is 59,570 square kilometres (23,000 sq mi) the largest river deltas in the world.
The Ganges-Brahmaputra system has the third greatest average discharge of the world’s riversâ€"roughly 1,086,500 cubic feet (30,770 cubic metres) per second; approximately 700,000 cubic feet (19,800 cubic metres) per second of the total is supplied by the Brahmaputra alone. The rivers’ combined suspended sediment load of about 1.84 billion tons per year is the world’s highest. In the past the course of the lower Brahmaputra was different and passed through the Jamalpur and Mymensingh districts. In a 7.5 magnitude earthquake on 2 April 1762, the main channel of the Brahmaputra at Bhahadurabad point was switched southwards and opened as Jamuna due to the result of tectonic uplift of the Madhupur tract.
Flooding
During the spring season (Juneâ€"October), floods are a very common occurrence. Deforestation in the Brahmaputra watershed has resulted in increased siltation levels, flash floods, and soil erosion in critical downstream habitat, such as the Kaziranga National Park in middle Assam. Occasionally, massive flooding causes huge losses to crops, life and property. Periodic flooding is a natural phenomenon which is ecologically important because it helps maintain the lowland grasslands and associated wildlife. Periodic floods also deposit fresh alluvium replenishing the fertile soil of the Brahmaputra River Valley. Thus flooding, Agriculture, and agricultural practices are closely connected. Flood control measures are taken by water resource department and the Brahmaputra Board but until now the flood problem remains unsolved. At least a third of the land of Majuli island has been eroded by the mighty river. Recently it is suggested that a highway protected by concrete mat along the river and excavation of the river bed can curb this menace. This project, named The Brahmaputra River Restoration Project, is yet to be implemented by the Government.
International cooperation
The waters of the River Brahmaputra are shared by China, India, and Bangladesh. In the 1990s and 2000s, there was repeated speculation about China building a dam at the Great Bend, with a view to divert the waters to the north of the country. This was denied by the Chinese government for many years. At the Kathmandu Workshop of Strategic Foresight Group in August 2009 on Water Security in the Himalayan Region, which on a rare occasion brought together leading hydrologists from the Basin countries, the Chinese scientists argued that it was not feasible for China to undertake such a diversion. However on 22 April 2010, China confirmed that it was indeed building the Zangmu Dam on the Brahmaputra in Tibet, but assured India that the project would not have any significant effect on the downstream flow to India.
In a meeting of scientists at Dhaka at 2010, 25 leading experts from the Basin countries issued a Dhaka Declaration on Water Security calling for exchange of information in low flow period, and other means of collaboration. Even though the UN Convention on Trans-boundary Water of 1997 does not prevent any of the Basin countries from building a dam, Customary Law offers relief to the lower riparian countries. Also, there is potential for China, India and Bangladesh to develop hydroelectricity projects and transboundary water navigation.
History
Early accounts give its name as Dyardanes. In the past the course of the lower Brahmaputra was different and passed through the Jamalpur and Mymensingh districts. Some water still flows through that course, now called the Old Brahmaputra, as a distributary of the main channel.
A question about the river system in Bangladesh is when and why the Brahmaputra changed its main course, at the site of the Jamuna and the "Old Brahmaputra" fork that can be seen by comparing modern maps to historic maps before the 1800s. It is likely that the Brahmaputra flowed directly south along its present main channel for much of the time since the Last Glacial Maximum, switching back and forth between the 2 courses several times throughout the Holocene.
One idea about the most recent avulsion is that the change in the course of the main waters of the Brahmaputra took place suddenly in 1787, the year of the heavy flooding of the river Tista. It is, however, well known that the Tista has always been a wandering river, sometimes joining the Ganges, sometimes being shifted westwards by the superior strength of that river and forced to join the Brahmaputra.
In the middle of the 18th century there were at least three fair-sized streams flowing between the Rajshahi and Dhaka Divisions, viz., the Daokoba, a branch of the Tista, the Monash or Konai, and the Salangi. The Lahajang and the Elengjany were also important rivers. In Renault's time, the Brahmaputra as a first step towards securing a more direct course to the sea by leaving the Mahdupur Jungle to the east began to send a considerable volume of water down the Jinai or Jabuna from Jamalpur into the Monash and Salangi. These rivers gradually coalesced and kept shifting to the west till they met the Daokoba, which was showing an equally rapid tendency to cut towards the east. The junction of these rivers gave the Brahmaputra a course worthy of her immense power, and the rivers to right and left silted up. In Renault's Altas they very much resemble the rivers of Jessore, which dried up after the hundred mouthed Ganges had cut her new channel to join the Meghna at the south of the Munshiganj subdivision.
In 1809, Buchanan Hamilton wrote that the new channel between Bhawanipur and Dewanranj "was scarcely inferior to the mighty river, and threatens to sweep away the intermediate country". By 1830, the old channel had been reduced to its present insignificance. It was navigable by country boats throughout the year and by launches only during rains, but at the point as low as Jamalpur it was formidable throughout the cold weather. Similar was the position for two or three months just below Mymensingh also.
As early as in 1830 there were resumption proceedings for chars which had formed in the new bed. Enquiries showed that many of the new formations were on the site of permanently settled villages which had been washed away by the changes in the course of the Jamuna and the Daokoba. The process has gone on ever since, and Buchanan Hamilton's remarks on the villages of Bengal are specially applicable to this area. He says that "a change in the site of a village 4 or 5Â miles causes little inconvenience and is considered no more than a usual casualty, which produces on the people no effect of consequence. Even the rich never put up buildings of a durable nature.
Other Usage
The BrahMos missile, which is a short range ramjet supersonic cruise missile that can be launched from submarines, ships, aircraft or land, is named after a portmanteau formed from the names of two rivers, the Brahmaputra of India and the Moskva of Russia. It is a joint venture between the Russian Federation's NPO Mashinostroeyenia and India's Defence Research and Development Organisation (DRDO) who have together formed BrahMos Aerospace Private Limited. It is based on the Russian P-800 Oniks cruise missile and other similar sea-skimming Russian cruise missile technologies.
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See also
- List of rivers in Bangladesh
- List of rivers in China
- List of rivers in India
- List of rivers of Asia
- List of rivers of Assam
- BrahMos missile
- Defence Research and Development Organisation, India
- NPO Mashinostroeyenia, Russia
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